Horizontal cleavage tear of discoid medial meniscus diagnosed on MRI and treated with arthroscopic partial resection

Surgical Management of Medial Discoid Meniscus in Pediatric and Adolescent Patients

BACKGROUND

Medial discoid meniscus (MDM) is an exceedingly rare anatomic abnormality that presents similarly to other meniscal pathologies. Symptomatic MDM is typically managed arthroscopically with mixed short-term and long-term outcomes, although the existing knowledge about MDM is limited. The purpose of this study was to describe the presentation and surgical treatment of MDM in pediatric and adolescent patients.

METHODS

Medical records of 12 knees with MDM in 8 pediatric and adolescent patients treated between 1991 and 2016 were reviewed retrospectively for patient characteristics, clinical manifestations, radiographic findings, operative techniques, and surgical outcomes.

RESULTS

Of the 446 knees diagnosed arthroscopically with discoid menisci, lateral discoid meniscus was noted in 434 knees (97.3%) and MDM was present in 12 knees (2.7%). The MDM series included 8 patients of mean age 13.8 years (range: 7.8 to 19.8), of which 5 were males (63%), and 4 (50%) had bilateral involvement. Of the 11 knees with available clinical records, all cases presented symptomatically (pain, mechanical symptoms); 10 (91%) had concurrent physical exam findings. On intraoperative examination, discoid morphologies were described as complete in 4/8 knees (50%) or incomplete in 4/8 (50%), with associated instability in 6/12 (50%). Meniscal tears were reported in 9 cases (75%)-primarily, horizontal cleavage tears. Saucerization was performed in 11 knees (92%), with medial meniscal repair in 7 (58%), when indicated. Retear of the medial meniscus occurred in 4/11 knees (36%) at a mean of 25.8 months postoperation; 2 knees required revisions. One knee developed arthrofibrosis and underwent arthroscopic lysis of adhesions.

CONCLUSIONS

MDM is a rare diagnosis, representing 3% of all discoid menisci, with a nonspecific clinical manifestation. Operative management of symptomatic MDM typically involves saucerization and meniscal repair, when indicated, for concurrent tears. Symptom resolution is common short-term, but long-term outcomes include recurrent meniscal tears. Subsequent observational studies are important to evaluate long-term outcomes, such as arthritic changes, with the advancement of arthroscopic techniques for meniscal preservation.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Arthroscopic Saucerization of a Symptomatic Posterior Horn Tear in a Discoid Medial Meniscus

Background: Discoid medial meniscus is an extremely rare congenital anatomic variant with an estimated incidence of 0.12%. Arthroscopic meniscal saucerization and repair are reserved for symptomatic tears only. We present a case of discoid medial meniscus tear, outline the surgical arthroscopic technique used for treatment, and compare several surgical approaches.

Case Report: An 18-year-old male presented with left knee pain and mechanical symptoms present for 2 years. Physical examination showed stability to both varus and valgus stresses with absence of locking or catching on McMurray testing. Magnetic resonance imaging confirmed discoid medial meniscus with a horizontal oblique tear of the posterior horn. The patient underwent saucerization of the left discoid medial meniscus and medial meniscus repair.

Conclusion: Discoid medial meniscus predisposes individuals to meniscal tears that often require operative management. Careful consideration of surgical approach can help to optimize patient outcomes while minimizing the risk of iatrogenic injury.

Intra-substance meniscal changes and their clinical significance: a meta-analysis

The degeneration of radial tie fibres of the central meniscal layer, and thinning of its lamellar layer results in increased intensity signals on magnetic resonance imaging, making it difficult to differentiate from true meniscal tear. This study aimed to assess the rate of encountered MRI grades 1 and 2 intrasubstance meniscal changes, and to set guidelines to report these changes based on predicted clinical outcome. A systematic review approach was employed using search engines, libraries, and databases (Google Scholar, ERIC, PubMed, and Medline) to search for scholarly sources on meniscal lesions and their significance in MRI published between 1 January 2000 and 30 June 2019. It retrieved 2750 abstracts, out of which 2738 were excluded and 13 studies meeting inclusion criteria were meta-analysed. It found an association between intrasubstances meniscal changes and outcomes. It resulted that intrasubstance meniscal changes were preservable through the protective functioning of the meniscus. Other than weight gain, no other significant risk factor of developing true meniscal tears later in life was found. It is important to examine intrasubstance meniscal change when patients suffer from mechanical meniscal symptoms especially in old age.

Discoid lateral meniscus: current concepts

The discoid meniscus is a congenital morphological abnormality encountered far more commonly on the lateral than the medial side. The discoid lateral meniscus (DLM) is more prevalent in Asia with an incidence of 10%-13%, than in the Western world with an incidence of 3%-5%. DLM can be bilateral in more than 80% cases. Due to its abnormal shape and size, the discoid meniscus is prone to tearing and has an impact on gait mechanics. The discoid meniscus has deranged collagen arrangement and vascularity which can have implications for healing after a repair. Patients with a DLM may or may not be symptomatic with mechanical complaints of locking, clicking, snapping or pain. Symptoms often arise due to a tear in the body of the meniscus or a peripheral detachment. Asymptomatic patients usually do not require any treatment, while symptomatic patients who do not have locking are managed conservatively. When a peripheral detachment is present, it must be stabilised while preserving the meniscus rim to allow transmission of hoop stresses. Rehabilitation after surgery is highly individualised and return to sports is possible after more than 4 months in those undergoing a repair. The functional outcomes and onset of radiographic arthritis after saucerisation and repairing a discoid meniscus are better in the long term, compared with a subtotal meniscectomy. However, there is no compelling evidence currently favouring a repair as results deteriorate with increasing follow-up. Poor prognosis is reported in patients undergoing a total meniscectomy, a higher age at presentation and valgus malalignment.

Meniscal allograft transplantation for symptomatic knee after meniscectomy of torn discoid medial meniscus: Report of three cases

In symptomatic discoid medial meniscus, partial meniscectomy is the principal treatment method and can yield promising short-term results. However, unlike the nondiscoid meniscus, discoid medial meniscus is frequently associated with horizontal cleavage tears, attributable to the presence of myxoid degeneration in the intrameniscal substance, in that it may potentially occur deteriorating long-term results because of re-tearing of remaining meniscus or secondary degeneration of cartilage of the medial compartment after meniscectomy. We experienced three rare cases of retear or secondary degeneration of cartilage of the medial compartment after meniscectomy for two patients with torn bilateral meniscus. Both patients were highly active young males. Meniscal allograft transplantation in complicated discoid medial meniscus was performed. At 2 years after meniscal allograft transplantation, clinical outcomes were improved with a normal range of motion. Orthopedic surgeons should recommend activity modification to prevent possible complicated injury of the discoid medial meniscus. Meniscal allograft transplantation may be an alternative option in highly active young patients undergoing complicated discoid medial meniscus to diminish pain, improve knee function, and prevent or delay degeneration.

Risk factors for radiographic progression of osteoarthritis after partial meniscectomy of discoid lateral meniscus tear

INTRODUCTION

Partial meniscectomy has been preferred in the treatment of discoid lateral meniscus (DLM) with tear, rather than total or subtotal meniscectomy, which could lead to late radiographic degenerative changes.

HYPOTHESIS

One or more risk factors contribute to radiographic progression of osteoarthritis after partial meniscectomy of DLM tear.

MATERIAL AND METHODS

Inclusion criteria were consecutive patients who underwent arthroscopic surgeries for DLM tear from January 2005 to December 2010 by one surgeon. Exclusion criteria were preoperative osteoarthritis with KL grade 3 or more, osteochondritis dissecans, minimal width of meniscal remnant less than 6mm after meniscectomy, meniscal repair of an unstable discoid meniscus, age over 60years, loss to follow-up for a minimum of 5years and simultaneous surgery on articular cartilage or anterior cruciate ligament. According to the KL grade at the last follow-up, all enrolled knees were sorted into no progression to knee osteoarthritis (KL grade 1 or 2 - NOA) and progression to osteoarthritis (KL grade 3 or 4 - POA) groups. Multivariate logistic regression was used to analyze the risk factors of high-grade osteoarthritis.

RESULTS

In comparison with NOA group (n=135) and POA group (n=67), prolonged symptom duration, increased relative percentage of DLM thickness (RPDT) and the presence of horizontal tear were significant risk factors. The presence of horizontal tear (P=0.048, adjusted OR=19.364) was the strongest predictor, compared with prolonged symptom duration (P=0.030, adjusted OR=1.150) and increased RPDT (P=0.003, adjusted OR=1.377).

DISCUSSION

Horizontal tear, prolonged symptom duration, and increased RPDT are significant risk factors for radiographic progression to high-grade osteoarthritis after partial meniscectomy of DLM tear with a minimum follow-up of 5years.

LEVEL OF EVIDENCE

III, case-control study.

Arthroscopic Saucerization and All-Inside Repair of a Delaminated Discoid Lateral Meniscus

Preservation of the meniscus has been shown to influence the progression of degenerative changes of the knee. As more meniscus is preserved, the propensity for development of osteoarthritis is lessened. Surgical treatment of a torn discoid meniscus has typically been a subtotal meniscectomy or partial meniscectomy. Similar to tears of a normal meniscus, partial meniscectomy compared with subtotal meniscectomy of the discoid meniscus confers better long-term results. With the abnormal morphology predisposing the discoid meniscus to tearing, several characteristic tear patterns can be observed-the horizontal tear being commonly encountered. We present a technique that not only creates a more normal morphology of a discoid meniscus but also preserves the tissue by using an all-inside, intrameniscal repair technique. This technique restores the central rim of the meniscus in the setting of a horizontal cleavage plane, thus restoring a more normal meniscus morphology.

Clinical features and prognosis of discoid medial meniscus

PURPOSE

To evaluate the clinical manifestations and the outcome of surgical treatment of discoid medial meniscus.

METHODS

Records of 13 patients with discoid medial meniscus were retrospectively reviewed for their epidemiology, clinical manifestations, operation methods, treatment outcome and radiographic characteristics.

RESULTS

The 13 cases of discoid medial meniscal injury took up 1.5 ‰ of the overall meniscal injuries treated at our institute during the 44-year period. Patients presented with knee pain (13 patients), giving away (10 patients), swelling (9 patients) and snapping (9 patients). The most common physical signs were medial joint line tenderness (13 patients) and positive McMurray test (11 patients). Ten patients required total meniscectomy. There were excellent short-term results: the median Tegner score was 7, and the mean Lysholm score was 94.8 ± 2.4 at two-year follow-up. However, the long-term outcome was not as good with degenerative changes in the medial compartment of all the involved knees.

CONCLUSION

The discoid medial meniscus is extremely rare. The clinical signs and symptoms of discoid medial meniscal injuries are similar to those of any other meniscal injury. No Wrisberg-ligament type abnormality was found. Meniscectomy for discoid medial meniscus produced promising short-term results and deteriorating long-term results with secondary degeneration of cartilage in the medial compartment.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Snapping knee: imaging findings with an emphasis on dynamic sonography

OBJECTIVE

The purpose of this article is to illustrate the causes of snapping knee. The value of imaging techniques is discussed with an emphasis on dynamic sonography in light of the available surgical and radiologic literature.

CONCLUSION

Because of its dynamic capabilities, dynamic sonography provides real-time visualization of snapping knee syndrome and may be used as a first-line modality.

The effect of meniscal tears on cartilage loss of the knee: findings on serial MRIs

BACKGROUND

The relationship between meniscal tears and progressive loss of hyaline cartilage and osteoarthritis of the knee has been reported in the literature. The current treatment protocols for meniscal tears include conservative treatment, meniscal repair, and meniscectomy. Treatment plans are based on factors such as tear pattern, patient age, and associated pathology. The mechanism, pattern, and treatment of meniscal tears vary with age and activity level. Younger, more active patients often sustain more acute tears, which are more amenable to repair due to increased propensity for healing compared with older patients. It is unclear which patients or types of meniscal tears will go on to sustain cartilage loss or osteoarthritis.

OBJECTIVE

In our study, we aimed to determine magnetic resonance imaging (MRI) findings in patients with meniscal tears that may be predictive as a risk factor for future cartilage loss.

METHODS

A database was retrospectively searched for patients with ≥ 2 MRIs of the same knee over a 7-year period, with the initial report containing the keyword "meniscal tear." Follow-up examinations were then evaluated for cartilage loss.

RESULTS

Seventy-six meniscal tears were evaluated. Initial MRI findings associated with cartilage loss included subchondral bone marrow edema (P < 0.0001), meniscal extrusion (P < 0.001), radial meniscal tear (P = 0.017), and posterior horn meniscal tear (P = 0.031). In patients without meniscectomy, cartilage loss was observed in 38% (15/39) compared with 76% (28/37) in patients with meniscectomy, (P = 0.0001).

CONCLUSION

Subchondral bone marrow edema and meniscal extrusion were the strongest MRI predictors for cartilage loss in an untreated knee with a meniscal tear. There was significantly greater cartilage loss in patients post-meniscectomy at follow-up than in those who did not undergo meniscectomy.